KAWAMURA, Y. 
shivering can occur in the presence of cortical barbiturate spindling 
without ACH injection. After ACH injection the frequency and number 
of NMU discharges decreased; after epinephrine injection, both in- 
creased, as did the number of NMU's per grouped discharge. 
Relationship of Body Temperature to Shivering 
As mentioned earlier shivering did not occur during deep anes- 
thesia. At room temperature (15 Cto20 C) the rectal temperature 
of animals gradually declined post Na-amytal injection and shivering 
occurred spontaneously at a mean rectal temperature of 34.4 C 
(range 30.7 C to 38.5 C) when animals were left unmolested. Such 
shivering was inhibited by radiant heating on the back with a mean 
time of 77 sec (range 15 to 180 sec) (Fig. 12). 
Shivering returned an average of 71 sees (range 20 to 260 sees) 
after the radiant heating was removed despite rising rectal temper- 
ature. Slow body warming by dipping one hind limb in 43 C water 
inhibited shivering at a rectal temperature of 39.5 C, but if the limb 
was removed from the water, shivering occurred at a rectal temper- 
ature of 39.2 C. Shivering at high rectal temperature was inhibited 
by radiant back heating and resumed when the heating was removed 
without change in rectal temperature (Fig. 13). 
o 
With a simimer environmental temperature of 26 C or more, 
it was always difficult to produce shivering under barbiturate anes- 
thesia even if the animal's environmental temperature was lowered 
o o 
to 10 - 15 C, the normal winter environmental temperature. 
Effects of Noxious Stimuli on Shivering 
As mentioned earlier, shivering could be produced by noxious 
stimuli when the animals were at an anesthetic level associated with 
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